Raptiva Filed for FDA Approval
Review process for Raptiva could take 10 months or more
First posted Dec. 23, 2002
Genentech and XOMA announced on Dec. 23, 2002, that they have submitted data to the U.S Food and Drug Administration (FDA) to evaluate the use of efalizumab for the treatment of moderate to severe plaque psoriasis. Efalizumab is known by the brand name Raptiva. Consumers will probably have to wait nearly one year before they can get Raptiva.
The filing includes data from three randomized, placebo-controlled efficacy studies. Over 2,100 patients with moderate to severe psoriasis were treated with Raptiva (efalizumab)--1,409 patients from the three phase III studies and 730 patients from supportive studies.
What is Raptiva?
Raptiva is a humanized monoclonal antibody in development for the potential treatment of plaque psoriasis in patients 18 years and older. It formerly was known as Xanelim and anti-CD11a. In the phase III studies, Raptiva was given as a once-a-week subcutaneous injection over 12 weeks.
Raptiva is part of a new generation of targeted therapies called "biologics" that selectively fight psoriasis at the cellular level. These drugs appear to have a more promising short-term safety profile than the treatment options now available to people with moderate to severe psoriasis, but long-term effects are unknown.
How does Raptiva work?
It is now widely accepted that psoriasis is caused by miscues in the human immune system that ultimately lead to accelerated growth of skin cells and the formation of the red, scaly lesions characteristic of the disease. Raptiva is designed to block a key immune-system reaction involved in the development of psoriasis.
In psoriasis, T cells (a type of white blood cell) "misfire" and fuel the development of psoriasis lesions. Raptiva prevents T cells from activating and triggering other immune responses. This prevents T cells from binding to antigen presenting cells (APCs), limiting T-cell activation. By blocking these receptors, Raptiva also prevents movement of T cells into tissues, including the skin.
Because Raptiva is a protein, it would be digested if taken orally. Raptiva is given by subcutaneous (under the skin) injection once a week. It can be done at home. Once it is stopped, the effects of psoriasis return. It is believed that psoriasis returns because the T cells are still present in circulation--the therapy prevents the T cells from entering the skin, but they return to body tissues when the therapy ends.
What are the side effects?
Raptiva was reported to be well tolerated, but side effects observed during the trials included mild-to-moderate headache, nausea, chills and pain. In the clinical trials, the side effects were reported to go away after patients stopped taking Raptiva.
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